$ { \left[\begin{array}{rr}{3} & {1} \\ {0} & {-2} \\ {4} & {0}\end{array}\right]-\left[\begin{array}{rr}{3} & {-1} \\ {0} & {4} \\ {3} & {1}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{3}-{3} & {1}-{-1} \\ {0}-{0} & {-2}-{4} \\ {4}-{3} & {0}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {2} \\ {0} & {-6} \\ {1} & {-1}\end{array}\right]}$